1z0-076 Practice Questions

Enterprise Manager Cloud Control offers comprehensive monitoring capabilities for Oracle Data Guard environments. It enables monitoring the rate at which redo is being applied on a logical standby database (A), which is crucial for ensuring that the standby database is keeping up with the changes from the primary. It also allows setting thresholds on performance metrics, such as the redo generation rate on the primary database (B), to alert administrators when values exceed critical or warning thresholds. Additionally, it provides the capability to estimate the potential data loss in the event of a disaster (E), helping in disaster recovery planning and ensuring business continuity.

Logical standby databases are a key feature of Oracle Data Guard and offer several distinct advantages, especially in terms of flexibility for reporting, upgrades, and disaster recovery:

Disaster-recovery solution with switchover and failover options (A):Logical standby databases provide a robust disaster-recovery solution, ensuring that any data updated on the primary database can be recovered. They support both switchover and failover operations, allowing for smooth role transitions between the primary and standby databases.

Used for reporting workloads requiring additional indexes or materialized views (B):Logical standby databases can be opened for read-write operations and can have additional indexes or materialized views that are not present in the primary database. This makes them ideal for offloading reporting and querying workloads from the primary database.

Snapshot standby databases are a feature of Oracle Data Guard that allows a physical standby database to be temporarily converted into a read-write database for testing or other purposes. The true statements about snapshot standby databases are:

FLASHBACK DATABASE is enabled automatically on a snapshot standby database after converting it from a physical standby database if not already enabled (B):When a physical standby is converted to a snapshot standby, FLASHBACK DATABASE is automatically enabled to allow the database to be easily reverted back to its original state.

FLASHBACK DATABASE is enabled automatically on a physical standby database as part of the conversion into a snapshot standby database, if not already enabled (C):As part of the conversion process, FLASHBACK DATABASE is turned on to ensure that changes made while the database is in snapshot standby mode can be undone.

A snapshot standby database may be opened read-write (E):Once a physical standby is converted to a snapshot standby, it can be opened for read-write operations, allowing for testing and other tasks that require a writable database.

The DBMS_ROLLING package facilitates a rolling upgrade process across a Data Guard configuration. The START PLAN procedure in particular handles several critical actions, including:

Creating a guaranteed restore point on the standby databases (B):This ensures that the standby databases can be reverted to their state before the rolling upgrade process in case of any issues.

Building a LogMiner dictionary on the primary database instance (C):This is necessary for logical standby databases to interpret redo data during the SQL Apply process.

D.  

E.  

The output shows that theFS_FAILOVER_STATUSisBYSTANDER, which indicates that the database in question is not actively involved in a fast-start failover configuration as a primary or standby. It is in a bystander role, meaning that while it is part of a Data Guard configuration, it is neither a target for failover nor actively participating in failover operations. Additionally,FS_FAILOVER_OBSERVER_HOSTshows 'cats', which indicates the host where the observer process is expected to run. However, since there is no information about the observer being present, we can infer that although 'cats' is designated for the observer to run, the observer is not currently connected to this database.

References

Oracle documentation on Data Guard configurations and theV$DATABASEview which provides information about the fast-start failover status and observer host.

Based on Oracle Database 19c: Data Guard Administration documents, the three measures that can prevent clients from connecting to the wrong database instances during switchovers, failovers, or regular operations in a Data Guard environment are:

B.  

The standby database services must be defined statically with the Listeners running on the standby database hosts.

D.  

The client applications must use the correct TNS entries when requesting connections to the database instances.

E.  

Client TNS entries for the databases use the correct service names for the intended service.

In an Oracle Data Guard configuration, correctly configuring Oracle Net Services (including TNS entries and listeners) is crucial for ensuring that clients connect to the appropriate database instance, whether it's the primary or standby. Defining services on the standby database and associating them with listeners ensures that client applications can connect to the standby when needed, especially useful in a role transition or when the standby is open for read-only access or real-time query. It's essential that TNS entries used by client applications specify the correct service names that correspond to the intended database roles, such as primary or standby. This setup facilitates seamless connectivity to the appropriate instance based on the role, especially critical during switchovers and failovers when the roles of the databases change.

Global Sequences are Oracle sequences that generate unique values across multiple instances in an Oracle RAC or a Data Guard configuration. Regarding their behavior and performance when connected to a physical standby database with Real-Time Query enabled:

A: The usage of Global Sequences can indeed have a performance impact on the primary database due to the need to generate unique values that are consistent across both primary and standby databases.

D: The performance impact on the physical standby database may occur if theCACHEsize is too small. This is because the standby database will frequently have to access the primary database to replenish the cache, which can increase the load and potentially lead to performance degradation.

E: Global Sequences should have theNOORDERandCACHEoptions set. TheNOORDERoption ensures that sequence numbers are provided without guaranteeing sequence order, thus improving scalability and performance. TheCACHEoption is used to specify how many sequence values will be held in memory for faster access.

Option B is incorrect as theLOG_ARCHIVE_DEST_nparameter's definition for standbys pointing back to the primary does not directly pertain to the creation of sequences.

Option C is incorrect because there is no requirement that the size of the cache for a sequence must be at least 100. TheCACHEsize can be set to a different number based on specific use cases or performance considerations.